docs: def _get_gc2_coordinates_for_rupture(self, edge_sets):
          """
          Calculates the GC2 coordinates for the nodes of the upper edge of the
          fault
          """
  
          # Establish GC2 length - for use with Ry0
          rup_gc2t, rup_gc2u = self.get_generalised_coordinates(
              edge_sets[:, 0], edge_sets[:, 1])
          # GC2 length should be the largest positive GC2 value of the edges
          self.gc_length = numpy.max(rup_gc2u)